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Indium Resources
Indium is the 49th element, abbreviated as In. Discovered in 1863, indium rarely is found as an isolated element. Alloys of indium have low melting points and are good semiconductors; it's use in LCD displays has recently increased the demand for Indium. Where is Indium found? Indium is not found in pure indium deposits in the earth. The main occurrence of Indium is with other metals in ores of zinc, copper, lead and tin.Jorgenson, John D.; George, Micheal W. "Mineral Commodity Profile Indium". United States Geological Survey. Indium appears in small amounts in the sulfides of these metals. The most common source of indium is in the zinc sulfide ore called sphalerite."Mineral Commodities Summary 2007: Indium" (pdf). United States Geological Survey. Retrieved 2013-4-17. Indium can also be found in volcanic sulfide deposits, and the highest concentrations can be found in vein deposits of tin and tungsten. However, it is not easy to recover the indium from these deposits economically. The main source for the indium we use in the world is as a byproduct from zinc and tin production. The main producer of Indium in the world is China, accounting for about one half of the world’s production.Tolcin, Amy C."2011 Minerals 2011: Indium" (pdf). United States Geological Survey. Retrieved 2013-4-17. As of a 2002 US report, the remaining indium was produced in France, Japan, Canada, Belgium, Russia, and Peru (in order of decreasing production). In the 1990s Indium’s price peaked and due to a fear about supply at the time, recycling of Indium peaked in the U.S. Since then recycling of Indium in the U.S. has declined, but recently (2011) Japan and South Korea have increased their recycling of Indium, so an additional source of Indium in the world is through recycling. How is Indium obtained? Almost all of Indium is produced as a byproduct of zinc production. A small amount is produced from tin production. Indium is produced from the slag of zinc production (the waste matter separated from metals during the smelting or refining of ore) using a leaching process. Leaching is an technique used to extract metals which converts them to an aqueous state. Indium is leached using HCl or H2SO4 . There are many different processes to extract Indium from the zinc slag, and they vary from processor to processor. One example is the jarosite process, which is shown in an infograph (see right). Indium’s path is highlighted. Indium recovered from this process is metal of a low-grade. It is further refined to be a high purity metal in refineries. Indium is produced in a lot of different forms, such as foil, ribbon, ingot, plates, powder, shot and pellets, and wire. What are the Uses of Indium? Due to Indium having a smaller number of valence electron than the Group IV semiconductors, indium is used in electronics as a dopant for semiconductors Germanium and Silicon, as well as doping indium arsenide with indium phosphide for use in heavy duty thermoelectric material. By doping, the electrical properties of a semiconductor are changed. It is also used as a sealer for particle accelerators and in space equipment in the form of Indium-Mercury Oxide.Uses of Indium according to http://indium.atomistry.com/application.html Indium metal is used in nuclear reactors in place of mercury because of its ability to capture neutrons.The Mineral Yearbook http://minerals.usgs.gov. Indium, when combined with tin and oxygen to create indium tin oxide can be used for conductive purposes in LCD displays. It is transparent, so it works well for touch screen technologies.Uses of Indium according to http://www.indium.com/inorganic-compounds/indium-compounds/indium-tin-oxide/ Another major use of Indium is in the solar cell industry. Through the usage of CIGS (Copper Indium Gallium Sellenide), the photons received by the sun allow electrons to jump the bandgaps necessary to create energy. So, indium is quickly becoming an ever increasing component in the renewable energy field. http://en.wikipedia.org/wiki/Copper_indium_gallium_selenide_solar_cells Is Indium Sustainable? Indium production in the world, as of 2012, is at an all time high at about 670 metric tons produced annually. These reserves of indium are obtained from either refining processes of zinc or from recycling formerly used indium. US Geological Survey as of 2012. http://minerals.usgs.gov/minerals/pubs/commodity/indium/mcs-2013-indiu.pdf Currently, the demand for indium in the United States is roughly equal to the amount imported. We are importing 110 metric tons annually and consuming approximately 90 metric tons of Indium. US Geological Survey as of 2012. http://minerals.usgs.gov/minerals/pubs/commodity/indium/mcs-2013-indiu.pdf As a result of the steady increase in the necessity for Indium, ie. increase in LED screen production, a steady increase in the concern over Indium depletion is also occuring. Sources have a wide range of expectations for the exact time in which Indium will be used up. Some sources pick the date as specifically as the years 2025 and 2028 respectively.Indium depletion date according to terresacree.org http://terresacree.org/indiumanglais.htmIndium depletion date according to ScientificAmerican http://www.scientificamerican.com/article.cfm?id=how-much-is-left As a result, the need for the recycling or the reduction of the use of indium has increased. Companies such as Sharp have worked to further the recycling efforts of the resources that we have. The technique that they currently use takes advantage of the properties of indium to effectively extract it from LCD panel televisions. In order to extract it, LCD panels are first crushed into glass cullet (small chips) and then dissolved in an acid solution. It is a simple process using common chemicals that eliminates the need for large energy expenditures, such as those required to achieve high temperatures or high pressures. From this acid solution, Indium is extracted by reacting it out into its solid indium hydroxide form.Sharp's recycling procedure of Indium found in LCD LED televisions. http://www.sharpdirect.co.uk/environment/recycling-technologies/page/recyclingtechnologies What are the Global Impacts of Indium? The impacts of indium have far reaching impacts on the industialized world as we know it. For example, Indium is used to coat the bearings of high speed motors since it allows for the even distribution of lubricating oil. Indium is also used to dope Germanium to make transistors, make electrical components such as rectifiers, thermistors and photoconductors, and can be used to make mirrors that are as reflective as silver mirrors but do not tarnish as quickly.The Element Indium. http://education.jlab.org/itselemental/ele049.html As a result, one can see that indium has far reaching impacts to much of industry. Simply put, it is in a great deal of the things that humans interact with on a daily basis. Thus, a depletion of it would likely have a strong impact on consumers, both in the industrialized world and in third-world countries all around the world. In terms of health impacts, Indium is considered to be sufficiently dangerous to living organisms. However, Indium compounds are encountered rarely by most people, but all indium compounds should be regarded as highly toxic. Indium compounds damage the heart, kidney, and liver, and may be teratogenic.The Biological Impacts of Indium. http://www.lenntech.com/periodic/elements/in.htm Furthermore, Indium also does not appear to have any significant environmental impacts. Since it is not widely dispersed, if at all, in the environment, Indium seems to pose no immediate threat to land or marine life. However, the specific environmental effects from the substance have not been investigated.The Biological Impacts of Indium. http://www.lenntech.com/periodic/elements/in.htm While Indium is not mined directly, it's source, zinc mining, does have effects on the environment. Zinc occurs naturally in the earth, but human mining of zinc has greatly increased the amount of zinc in the environment. Mining sites and processes can lead to large amounts of zinc in the soil as well as zinc in ground water or rivers near the site.Illinois Department of Public Health Environmental Health Fact Sheet. http://www.idph.state.il.us/envhealth/factsheets/zinc.html Higher concentrations of zinc can have adverse effects fish and plants: affecting the amount of oxygen fish can carry in their blood and affecting the ability of plants to absorb other essential metals such as iron and manganese. http://en.wikipedia.org/wiki/Zinc#Environmental_impact References Category: Resource Mapping